Cartridge for firearms having sideloaded firing chambers



22, 1961 G. E. KUNZ 2,996,988

CARTRIDGE FOR FIREARMS HAVING SIDE-LOADED FIRING CHAMBERS Filed March 4, 1958 INVENTOR, GEORGE E. Kuuz.

United States Patent Ofice Patented Aug. 22, 1961 2,996,988 CARTRIDGE FOR FIREARMS HAVING SIDE- LOADED FIRING CHAIVIBERS George E. Kunz, Pacific Palisades, Califi, assignor to Hughes To'ol Company-Aircraft Division, Houston,

Tex., a corporation of Delaware Filed Mar. 4, 1958, Ser. No. 719,169 8 Claims. (Cl. 10238) This invention relates in general to guns and cartridges, especially to guns having side-loaded firing chambers instead of the customary end-loaded firing chambers, and in particular to cartridges adapted for side entry into the side-loaded chambers, and to cartridge cases with side walls of elastic material.

In a conventional gun or firearm, the firing chamber is a generally cylindrical compartment axially aligned with the bore of a gun tube and adapted to axially re ceive a generally cylindrical cartridge which is held in position by a suitable mechanism until after the gun is discharged. Once the cartridge is fired, reuse of the firing chamber requires removal of the spent cartridge case. Thus, the use of a conventional gun involves a loading operation wherein a cartridge received by the firing chamber, is moved an axial distance normally exceeding the overall length of the cartridge, and an ejection operation wherein the spent cartridge case is removed from the firing chamber by a reversal of the axial movement involved in the loading operation.

Obviously, time is required to move a cartridge into a firing chamber and to extract from said chamber the spent cartridge case; hence, the firing rate of a gun is materially afiected by the cartridge loading and case ejecting operations, a condition which appears'to have been recognized by many prior inventors as evidenced by United States Patents 1,307,316 and 1,340,791 issued June 17, 1919 and May 18, 1920 to I. F. OMalley and I. Pacifico, respectively. Both of these patents disclose indexable cylinders or drums having cartridge-receiving cavities in their outer surfaces extending axially of the drums such that cartridges arranged in belts enter the cavities sideways when the drums and belts are moved in unison. In each disclosure, indexing the drum not only moves cartridges to battery position, but it also moves the cartridge belt such that cartridges enter the drum cavities sideways while the spent cartridge cases egress in a similar manner.

Notwithstanding the improvements in firing rates afforded by the side-loaded guns in the above-mentioned patents, the side-loading principle has not been generally accepted in the art because of the difiiculty of adequately supporting a thin-walled cartridge of conventional design so as to preclude its rupture from stresses caused by pressures instantaneously produced when the cartridge is fired; and because of the fact that, with a thinwalled metal cartridge case even though its wall is well supported (against rupture) by components of a sideopening firing chamber, there is permanent radial expansion of the case sufiicient to prevent the necessary relative movement of the firing chamber component for effecting extraction of the spent case by forces normally available for that purpose. In other words, the need for unconventional firing chambers and special cartridges particularly adapted for functional cooperation to the extent that cartridge cases having relatively thin walls can be employed with no tendency to rupture or permanently expand from internal pressures produced when the cartridge is fired and to the extent that adequate obturation is obtained to prevent the escape of such internal pressures before the projectiles are ejected from the gun tube, have been effective obstacles in the development of side-loaded revolver type guns.

The present invention contemplates a cartridge especially adapted for use in a gun having a rotatable drum with side-loaded cartridge-receiving cavities, in which the cartridge case is a noncircular element with relatively thin wall sections reinforced where ruptures might occur, and constructed of plastic material in general or of plastic material having the resilient properties of an elastomer to provide the case with the ability to expand and/ or flow in response to internally-produced gas pressures for effecting obturation, and with ability to contract quickly for restoring the drum to its rotatable condition as soon as possible after the projectile leaves the gun tube.

It is also contemplated that the cross sectional contour of the noncircular cartridge case be such as to make it possible for a simplified cartridge-receiving cavity and an overlying sidepiece or side-block to provide complete support for all sides of the case when the cartridge is in battery position, i.e., with the projectile axially aligned with the gun tube. The term side-block has been selected to designate the side closure of the opensided cartridge cavity in contrast to the term breech block customarily employed to designate the breech-end closure of breech loaded guns. It is further contemplated that the cartridge include an internal framework cooperatively associated with the ends of the cartridge case for supporting the projectile within the axial limits of the case such that accidental distortion of the case walls will not affect projectile alignment.

Accordingly, it is an object of this invention to provide a cartridge for a gun having a side-loaded firing chamber, and to provide such a cartridge which is characterized by a molded-plastic cartridge case having a noncircular cross sectional contour such that simple firing chamber components can efiectively support all sides of the case when the cartridge is fired in the gun.

It is another object to provide such a cartridge which is capable of mass production for use in rapid-fire guns of the character employing revolvable elements having side-loaded cartridge-supporting cavities, which elements are adapted for movement relative to the tubes of the guns such that each cavity successively comprises a firing chamber axially aligned with a gun tube bore, and to provide such a cartridge of which the cartridge case is free from permanent radial expansion when fired in a side loaded firing chamber.

It is also an object to provide a gun cartridge in which a projectile is coextensively disposed within a cartridge case having a flexible perimetric side wall of elastic material and a rigid projectile-supporting framework interconnecting the end walls of the case for maintaining projectile alignment independent of the cartridge case side walls, and to further provide a cartridge of this character in which the projectile supporting framework is adapted to allow relative movement between the end walls of the case such that one end wall is forced into obturating engagement with the breech of a gun tube in response to gas pressures produced within the case when the cartridge is fired in a gun.

In a gun having a revolvable element with a plurality of open-sided cartridge receiving cavities, and a stationary side-block adapted for cooperation with the cavities so A hence it is a further object of the invention to provide that step-wise rotation of the element is effective for causing the side-block to successively close the open side of each cavity such as to comprise a cartridge firing chamber, it is essential that cartridges not only enter the cavities freely and their cases freely egress therefrom, but the sideblock and the walls of each cavity must fully cooperate with each other to embrace and support the walls of the cartridge case against the forces of expanding gas pressures produced within the case when a cartridge is fired;

a. cartridge having a case with a cross sectional contour especially adapted to achieve these essential functions, and to also provide such a cartridge wherein the case is reinforced along its length. in regions, adjacent the junctions formed between the side-block and the revolvable element while v a cavity of the elementand the sideblock comprise a firing. chamber. It is an additional object to provide suchv a cartridge case having end walls of non-elastic material and a perimetric side wall of elastic material, ofwhich, the latter is characterized byability to fiow'as a liquiddnresponse-to the forces produced by gas pressures resulting from combustion-of the propellant employed in the cartridge, and by the ability to return to its. normal shape when the gas pressures subside.

These and other objects and advantages will become more apparent from the following description considered in connection with the accompanying drawings. It is expressly understood, however, that the drawings are for they purpose of illustration and description only, and are not intended as a definition of the limits of the invention. In the drawings:

FIG. 1 isa. longitudinal section of a cartridge constructed according to this invention;

FIG. 2 is a cross sectional view taken on line 2-2 of FIG. 1;

FIG. 3 is a cross sectional view taken on line 3-3 of FIG. 1; v

FIG. 4-is a cross sectional view taken on line, 44 of FIG. 1;

FIG. 5 is a longitudinal section of the projectile-supporting framework employed in the cartridge of FIG. 1;

FIG. 6 is a perspective view of the cartridge shown in FIG. 1;

FIG. 7 is a sectional view taken longitudinally through the cylinder of a revolver-type gun;

FIG. 8 is a view taken on line 88 of FIG, 7 with a schematic showing of a cartridge belt; and

FIG. 9 is a cross sectional view of a cartridge case constructed according to this invention, showing a differentoutline as compared to the views in FIGS. 2 through 4.

Cartridge A illustrated in FIGS. 1 and 6 comprises in general, a projectile-supporting cage or open framework 10 interconnecting end walls 20 and 30 such as to constitute the self-sustaining structure seen in FIG. 5, a projectile 40. coextensiv ely disposed within the unitary struc-v ture, and a perimetric sidewall 50 connected to end walls 21) and 30 such as to comprise, a cartridge case, said perimetric wall surrounding framework 10 in radially spaced relationship to provide an annular powder chamber 60 around the framework and the projectile.

As shown in FIGS. 1 and 5, cage 10 is a hollow, generally cylindrical tubular element having portions 11 and 12 respectively provided with suitable perforations'such as elongated openings 13 and 1 4. One end of cage 10 identified by reference numeral 15, is internally threaded to threadedly receive an externally threaded boss 21 projecting from endwall'20; while the other end, identified byreference numeral 16, is crimped around the end cire curnference of tubular portion 31 projecting from end wall 30. Cage 10' is also provided with a solid-walled portion 17 separating portions 11 and 12, and having an internal shoulder provided with a radially-extending annular surface 1-8 adapted to engage the rearwardly-facing radially-extending annular surface 43- of a rotating band 42 associated with the base portion 41 of projectile 40.

It is to be noted'that end wall 30 andits projecting tubular portion 31 are respectively bored'to provide retainer; 70Qis providedwitha central openingsurroundedv -a-ltl t in a a -emailin akfiabl fla ge 2'- having a conical internal surface in engagement with a. portion of the conical external sunface of an ogival nose portion 45 of projectile 40 in the region near the main body of the projectile for holding said projectile against accidental movement outwardly of the case and suchthatthe radial surface 43 of rotating band 42- is in contact with the radialsurface 18 in portion 1 7 of cage 10.

To assemble projectile 40 with cage 10* and end wall 30, the projectile is pressed into the cage until radiallyextending annular surface 43 of the rotating band 42 rests firmly against radially-extending annular surface 18 of the internal shoulder formed in the solid-walled portion 17 of the cage; then retainer 70 placed over the nose of the projectile, is brought to the position where flange 71 is in contact with wall 19' by the distal end of tubular portion 31 of the end wall '30. Now, while cage 10, projectile.40, retainer 70, and end wall 30 are held in this position by any suitable means (not shown), end 16 of the cageis crimped into an annular groove in the circumference of tubular portion 31' of the end wall as indicated in FIG. 5 by reference numeral 34. When the crimping operation is completed the four elements involved become a self-sustaining assembly which, in effect, constitutes the backbone'of the cartridge, and which, with the addition of end wall 20 constitutes a unitary structure capable of supporting the projectile completely inde pendent of the perimetric side wall as hereinafter described.

, Perimetric wall 50' is a hollow tube-like element having end portions 51 and 52 respectively provided with axially aligned. openings having internal surfaces dimensioned to lit the circumferential surface of cage end portion 15 and the. circumferential surface oftubular portion 31 of end wall 30 not covered by cage end portion 16, such that the fitted surfaces can be cementitiously bonded together by a suitable cement or bonding agent. Element 5,0,is molded of. elastic material selected from the family. of elastomers or rubber-like compounds, for its resilient properties, its dimensional stability, strength andcompatibility with propellants, and its ability to avoid embrittlement at subzero temperatures. In this connection, several compounds from the silicone group ofelastomers haveproduced satisfactory results.

Inasmuch as cartridge A is primarily intended for use with guns having side-opening firing chambers, a gun of this. character identified by reference numeral is schematically illustrated in FIGS. 7 and 8 where a revolvable cylinder 81 having a plurality of cartridge receiving cavities 82 is rotatively supportedv in a frame or gun breech 83 by a pin 84 such that rotation of the cylinder is effective for causing alignment of each cavity with the bore of a guntube 85 attached to the breech. It is to be noted that cavities 82 are in efiect axially extending grooves of uniform cross section cut into the body of the cylinder for the full length thereof such that each cavity is open on both'ends of the cylinder as well as on the periphery thereof, and that the cross sectional contours of the grooves comprising the cavities 82. are in full agreement with the cartridge. In other words, the bottom.86 of each cavity is rounded to correspond to the rounded side 53 of tube-like element 50 (see FIG. 2), and the sides 87, 87 of each cavity slope divergently outward to the periphery of the cylinder so as to correspond with the sloping sides 54, 54' of element 50.

(Minder 81' of gun 80 is closely fitted to breech 83 with just enough clearance between the ends of the cylinder and breech walls 88, 89 and between the periphery of the cylinder and breech walls 90, 91 to permit .rotation of the cylinder with respect to the breech. Thus, when the cylinder is rotated to a position where one of the cavities 82 is axially aligned with the bore of gun tube 85, the .inner vertical surface of wall 88 and the innericylindri cal surface of wall Slllhereinafter referred to as SidGrblOQk 90, cooperates with cylinder 81 to close one end and the open side of the cavitysoas toconstiq,

ama s tute a firing chamber for a cartridge disposed therein, as shown in FIGS. 7 and 8.

In view of the rotatable relationship of cylinder 81 with respect to breech 83, breaks or gaps exist in the end walls and perimetric side wall of the firing chamber; hence, a cartridge case to be successfully employed in a firing chamber with these structural features must be adequately reinforced in the regions directly associated with such breaks or gaps to preclude rupture of the case or extrusion of the case material into the spaces comprising the breaks or gaps. Moreover, the case must be constructed to provide completely effective obturationbetween the case and the gun tube in a gun of this type in order to obtain optimum projectile velocity from the propellant employed.

Returning to the description of cartridge A, end Walls and 30 are, like element 50, contoured to agree with the cross sectional contour of the firing chamber as constituted by cavity 82 and the inner surface of sideblock 90; however, in view of the clearance necessary between the outer walls of the cartridge and the inner Walls of the firing chamber to permit the cartridge to be received by the cavity 82 and then be indexed with cylinder 81 into battery position as seen in FIGS. 7 and 8, there is some space in the firing chamber not filled by the cartridge, such for example, as the space between the ends of the cartridge and breech walls 88 and 89, and the space between wall 55 of element 50 and the inner cylindrical surface of side-block 90, together with any unfilled space which may exist in cavity 82. To fully understand the unique features of cartridge A, it is pointed out that the elastic nature of rubber or rubber-like compounds provides the material of tube-like element 50 with the ability to flow under pressure as a liquid flows under pressure. Thus, when a propellant 61 in chamber 60 is ignited by a primer in end wall 20, the resultant gas pressure not only expands the cartridge case such that walls 53, 54, 54' and 55 of element 50 are respectively forced against walls 86, 87 and 87' of cavity 82 and the inner cylindrical surface of side-block 90, and such that end walls 20 and are respectively forced against breech wall 88 and the projectile-entering end of gun tube 85 to the extent that effective obturation is provided, but the elastic material comprising element flows as a liquid under the influence of the gas pressure and tends to squeeze or extrude into any voids or spaces associated with the firing chamber.

To preclude squeezing or extruding the flowable mate rial of element 50 into the gaps formed by the clearance. between cylinder 81 and side-block 90 of the gun 80 when cartridge A is fired therein, the corners formed by the junctions of walls 54, 54' and 55 of element 50 are reinforced with suitable strips 56 and 56' made of nonflowable material such as resin-impregnated glass fibers. Thus, as element 50 expands under the influence of propellant gas pressure, the reinforced corners of the element 50 are forced into the corresponding corners of the firing chamber formed by the junctions of cavity walls 87, 87' and the inner surface of side-block 90 such that strips 56 and56' act to close the gap between the side block and cylinder 81 to the extent thatthe flowable material in walls 54, 54' and 55 of element 50 cannot enter the gaps. Before describing the means employed to preclude squeezing or extruding the flowable material of element 50 at the ends of the cartridge, it is again pointed out that, when cartridge A is fired in gun 80, end walls 20 and 30 are respectively forced against breech wall 88 and the projectile-entering end of gun tube 85. Therefore, the gaps into which the material of element 50 can flow result from the clearance between the outer rims of end walls 20, 30 and the walls of the firing chamber; namely, walls 86, 87, 87 and the inner cylindrical surface of sideblock 90; it being understood that end walls 20 and 30 are constructed of a nonflowable material such as metal. In view of the condition just described, ends 51 and 52 of element 50 are each provided with a circumferential groove adapted to respectively receive extrusion-prevent ing rings 57 and 57 made of nonflowable material such as resin-impregnated glass fibers, which rings are shown in cross section in FIG. 1; while plan views of rings 57 and 57' are respectively shown in FIGS. 3 and 4, where each ring appears as the unshaded border of the sections taken on lines 3-3 and 44 of FIG. 1. Although the material comprising rings 57 and 57' is of the nonfiowable type, each ring is sufliciently elastic to expand radially outward into fluid-tight contact with walls 86, 87, 87' and the inner surface of side-block 90 in response to the material of element St) flowing as a fluid under each ring in response to propellant gas pressure in chamber 60 of the cartridge; thus, material of element 50 is precluded from squeezing out around the rims of end walls 20 and 30.

It is important to note that movement of end walls 20 and 30 of cartridge A in opposite axial directions under the influence of propellant gas pressure in chamber 60 is accomplished without producing tensional forces in the walls of element 50, or in the cementitiously bonded connections of element ends 51 and 52 to cage end portion 15 and tubular portion 31 of end wall 30, respectively. These unique conditions result from the fact that the gas pressure forcing the end walls apart, is also applied to walls 53, 54, 5'4 and 55 of element 50 such as to cause the material thereof to flow if space is available into which it can flow; hence, when the end walls move away from each other, the wall material flows into the resulting space. In fact, the gas pressure applied radially to the inn r surface of the walls of chamber 60 is converted into axial pressure applied to end walls 20 and 30 because of the flowable characteristics of the elastic rubber-like material comprising element 50.

Because of the elastic qualities of the materials employed in the construction of element 50 and extrusionpreventing rings 57 and 57', the element and the rings return to their normal dimensions when gas pressure in chamber 60 is expended in propelling projectile 40 through the gun tube 85. With this return to normal size, gun cylinder 81 can be indexed for ejecting the spent cartridge case from its cavity 82 and a live cartridge can be side loaded into a cavity and moved to battery position.

. Cartridges of the character of cartridge A can be arranged in belt formation as schematically illustrated in FIG. 8, and the belt of cartridges identified by reference numeral 94 can be fed to gun '80 by pulling the belt in the direction indicated by arrow 95, or by rotating cylinder 81 such as to effect movement of the belt in the direction indicated by arrow 96. In either case, the cartridges are automatically loaded into and unloaded from cylinder cavities 82 through the open side thereof.

Whenguns are of the type in which ammunition belts are not feasible, such as pistols and/or rifles of small caliber, the side-loading and side-unloading features of gun can be realized even with loose cartridges, by constructing the cross sectional configuration of each cartridge according torcartridge B illustrated in FIG. 9. In this modification of cartridge A, the perimetric side wall of thecartridge case is divided into three portions of equal dimensions having the same curvature as the inner cylindrical surface of the side-block (FIG. 8) in other words, the outline of a cross section of the perimetric wall is that of an equilateral triangle having arcuate sides of equal curvature; it being understood that cavities 82 in cylinder 81 would be modified accordingly. The advantage of the triangular shape of cartridge B over cartridge A resides in the fact that cartridge B can enter the cartridge-receiving cavities of the gun cylinder in any one of three different ways; hence, the problem of matched positioning is eliminated. It is to be noted that all three corners of the tube-like element comprising the perimetric wall of cartridge B are reinforced by strips 98 which performthe identical function of"strips 56 and 56 previously described in connection with cartridge A.

What isclaimed as new is: v

1. A cartridge comprising: a generally cylindrical projectile member having a base portion provided with a radially-extending rearwardly-facing first surface and a nose portion provided With a forwardly-facing conical second surface; a first end wall having a primer; a second end wallhaving an exit opening for the passage of said projectile member, said second end wall including a tubular portion projecting toward said first end wall such that the bore of said tubular portion is aligned with. said exit opening; a cage-like framework of generally cylindrical configuration havingfirst and second tube-like end engaging the first and second surfaces of the projectilemember base and nose portions such as to fix the axial position of said member inthe cartridge and normally maintain said member in said position, said retaining means including an element contacting said second surface such that said nose portion is disposed coextensively within thealigned tubular portion bore and exit opening of the second end wall; and a perimetric side wall con structed of elastomer materialhaving rubber-like plasticity, extending between the first and second end walls and surrounding the framework such as to provide an annular propellant chamber coextensive with said fr'amework; said perimetric sidewall having first and second end portions respectively receiving the first end portion of the framework and the tubular portion of the second end wall in gas-tight relationship effected by abonding agent therebetween; said first end wall being replaceably disconnectible from said framework for loading propellant material into said propellant chamber.

2. A cartridge of the character defined'in claim 1, in which the perimetric side wall is provided with an external contour of noncircular cross section wherein portions of said wall intersect such as to form corners extending throughout the length of the perimetric wall;

3. A cartridge of the character defined in claim- 2 in which the corners of said perimetric wall include reinforcing means. a

4. A cartridge comprising: a generally cylindrical projectile member having a base portion provided with a radially-extending rearwardly-facing first surface and a nose portion provided with a forwardly-facing conical second surface; a first end wallincluding an externally threaded projection and priming means for firing the car tridge; a second end wall having an exit opening for the passage. of said projectile member. when saidcartridge is fired, said second end wall including a tubularfportion projecting toward'tlie threaded projection of. the firstend wall such that said tubular portion is axially aligned with said. threaded projection and said exit opening; a cage-like framework of generally cylindrical configuration having first and second tube-like end portions of which the first tube-like end portion threadedly receives the threaded projection of the first end wall andthe second tube-like end portion is rigidly attached to the tubular portion of the secondend wall such that said framework and end walls constitute a self-supporting structure, said framework supportingly surrounding the projectile member such that said'member is supported by the self-supporting structure between the end walls thereof in axially aligned relationship with the bore of the tubular portion of the second ejndwall; a projectile-member retaining means structurally associated with said framework and engaging the first and second surfaces of the projectile member base andnose portions such as to establishthe axial position of said member in the cartridge andnormally maintain said member in said position, said means including a retaining'element having a flange portion contacting said second surface of the projectile-member nose portion such thatsaid' nose portion is positioned coextensively within the aligned tubular-portion bore and the exit opening of the second end wall; anda perimetric side wall extending between the first and second end Walls and surrounding the framework such as to provide an annular propellant chamber coextensive with said framework, said perimetric side wall having first and second end portions circumferentially embracing the first end portion of the framework and the tubular portion of the second end wall, respectively; the threaded. portion of the first end wall being replaceably separable from the first tube-like end portion of the cagelike framework so that said annular powder chamber can be loaded'with propellant material'after the cartridge has been fully assembled.

I 5'; Thecartridge defined inclaim 4 in which the perimetric side wall extending between the first and second endwalls is constructed of rubber-like material.

6. The cartridge defined in claim 5 in which the first and second end portions of the perimetric side wall are cementitiously bonded to the first end portion of the framework and the tubular portion of the scecond end wall, respectively.

7." A cartridge of the character defined in claim 6, in

which the'perirnetric side wall is provided with an external contour of non-circular cross section wherein portions of said wall intersect such as to form corners extending throughout the length of the perimetric wall.

8. A cartridge of the character defined in claim 7 in which the corners ofsaid perimetric wall include reinforcing means.

OTHER REFERENCES. Newsweek, pa esz, April 1, 1957. 

